A series of filters placed over a sensor, which allows colour information to be recorded. The most common variety is the Bayer RGB filter, which has red, green and blue filters arranged in a mosaic pattern. There are twice as many green filters as there are each red and blue, as this corresponds with the greater sensitivity of the human visual system to green. As each photosite only records information for one colour (determined by the filter above it), the values of the other two colours are estimated by a process known as demosaicing.